Latency is time delay - the lateness of one thing, compared to another / a reasonable referenc.
Latency from physics
Physical sound latency
Physical light latency
Device latency
Electronic latency
Inter-device latency: different devices aren't necessarily synced, nor communicate instantly
Compared to what?
Verifying
Digital audio latency
Audio output latency
Audio input latency
Wireless audio latency
TV latency
Computer latency
PC keyboard and mouse latency
PC graphics latency
PC monitor latency
PC multitasking latency
Experiment latency
DAW latency
"Latency compensation"